Thinking about a 3-way PA Driver Project, advice needed

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Everyone - after completing (and continuing to tune) my RS4 project I can say I'm firmly hooked back into speaker building and am already craving a bigger, bolder project.

I've always been fascinated with Pro Drivers and never really had the chance to do something really fun with them. Years ago I built the whole PA set up for a few churches locally but those were not audiophile systems by any means. It's been inspiring to see some of the really huge horn projects out there, and I certainly am not ready for a full horn setup, I'd love to build a set of audiophile quality speakers with PA output and "attack" performance.

Particularly what I'd like to produce audibly is the "snap, crack in your chest" that I've heard in PA speakers before, that fast, high efficiency performance a good PA driver can deliver. And I'd love for them to image and sound incredible and to learn a bunch of stuff too :p

This is the current rough design (see attached) I'm considering, it would be a type of Trans Lam but I have some neat ideas about how to pull off an enclosure this big w/o using 100 sheets of plywood :D Visually I love the look of the round cabinets stacked on top of each other. Overall height of about 4.5' and up to 3' deep. Tweeter to mid distance is by no means final and I'll definitely put those twi drivers as close to each other as possible.

Overall Concept:

1 - 18" subwoofer in approx 5ft ported enclosure up to 100Hz, 12" Midbass in sealed 1ft from 100-1500Hz, Compression Tweeter from 1500 up.
2 - Controlled with my Adcom stack and miniDSP for cross over and PEQ
3 - Would like to use a round horn for the CD if possible, for visual/size reasons as well as audibly.
4 - Was considering Selenium WS drivers for woofers and CD but totally open to what would work best.

Initial Questions:

1 - Any issue using a round horn, I like this combo and that they're matched from Selenium: https://www.parts-express.com/selenium-hl14-50n-2-exponential-horn-45x45-4-bolt--264-316 and https://www.parts-express.com/selenium-d3300ti-dpd-2-titanium-horn-driver-4-bolt--264-228 What horn configuration has worked well for you in the past, in this type of application?

2 - Anything substantially wrong in the concept or direction?

3 - Please tell me what I'm missing.

Thanks!
 

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1. That compression driver/horn combo will be pretty beamy. Consider a 1-1.4" exit driver with a 1.75-3" diaphram. The seos 12 has worked well for me although I prefer larger diaphram drivers for the room size and distance I have. Faital Pro and 18 Sound have some nice horns as well.

2. Cylinders are not the best shape for diffraction effects but might not be a problem with the sizes and crossovers you're using. Maybe try modeling in The Edge.

3. Consider the B&C 12PE32 for your midbass. It will contribute a lot to the PA impact and clarity you seek. When you're further along the way take a look at the Harsch crossover thread if you haven't already.
 
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1. That compression driver/horn combo will be pretty beamy. Consider a 1-1.4" exit driver with a 1.75-3" diaphram. The seos 12 has worked well for me although I prefer larger diaphram drivers for the room size and distance I have. Faital Pro and 18 Sound have some nice horns as well.

Thanks for the feedback, exactly what I need to know! Will check out those drivers

2. Cylinders are not the best shape for diffraction effects but might not be a problem with the sizes and crossovers you're using. Maybe try modeling in The Edge.
Yea visually the look I'm going for as well as WAF factor

3. Consider the B&C 12PE32 for your midbass. It will contribute a lot to the PA impact and clarity you seek. When you're further along the way take a look at the Harsch crossover thread if you haven't already.
Interesting driver, I just modeled an enclosure for it, seems to want something almost impossibly small like 5-10l, in your experience what has worked well for you with this driver? Would need it to go strong to 100hz.

Thanks again!
 
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I'd steer away from using cylindrical shapes as well, since they're the worst regarding diffraction issues. As stated, taken the directivity of the drivers, this might not be an issue, but still should be thoroughly investigated before deciding to build such known-to-be-bad shapes.

For the bass driver I'd suggest raising the low-pass point to around 250-300Hz. This way you'll have less to worry about floor bounce suck-out. And if you want that kick-drum punch, it's something that usually happens around that point, so more of that is produced by the larger diaphragm. One driver I've thought of for such a design is the 18Sound 18LW2400 (IIRC).

For the compression driver I'd go with something like a BMS or a B&C unit. With the BMS ring diaphragm drivers you might be able to squeeze a little more top end compared to more traditional dome compressors. In my experience both manufacturers make very good drivers. The lesser compression drivers aren't always that good when you want Hi-Fi. Something like a BMS 4550 or a B&C DE610 might be a good starting point.

For horns I'd probably go with 18Sound, and be sure to use something that has a compatible directivity pattern with your midrange driver. That Selenium horn might be too small a companion for a 12" midrange.

Oh, and I'd like to point out that in my experience all of the manufacturers I've mentioned (BMS, B&C and 18Sound) have been quite honest on their datasheets, which isn't always the case. There are several cases of misleading response graphs printed out on official datasheets by manufacturers. The companies I've mentioned have either given honest or "worse than truth" data through their marketing. But this is just my experience...
 
Thanks for the feedback, I'll definitely check out those drivers!

When it comes to edge diffraction, from my understanding it's more of an issue the higher the frequencies go correct? If so then I could still keep the sub somewhat round but then do a more rectangular baffle for the mid and tweeter, I just want to avoid building a rectangular PA box which is something that I could essentially buy anyways.

In addition to sounding really good, I want to look really good and be really unique as well as much as possible.

I'll download them play with the edge as well, I haven't used it but deafly something I want to look at

Good feedback on the sub will for crossover frequency as well, would you agree then I can run a smaller midrange like a 10 inch version then?

Thanks!


Sent from my iPhone using Tapatalk
 
These show up used pretty cheap from time to time. They use the incredible Audax midrange, and a B&C DE750 high driver along with a pair of Eminence Kappa 15"s. The complex crossover will need some parts upgraded and the cabinet could use additional bracing but with a bit of work you will have something amazing. Still one of my favorite mixed use, short range boxes! EAW: Eastern Acoustic Works | LA325 Passive Three-Way Trapezoidal Enclosure - EAW
 
IMO, it might be worth going for a 10" instead of a 12". Both will easily reach down to 1-200Hz to meet the 18", but the 10" will give you the option of a higher crossover point to the compression driver.

Since you've got DSP available, consider a closed box for the 18" - with some dynamic EQ (or a couple of settings that you can switch between), you could get a 20Hz lower cutoff for day-to-day listening, but when you want to crank it, cut off at 35Hz for some serious SPL.
A ported box has pretty much zero useful output below its tuning frequency, whereas sealed can go as low as you want, so long as you're willing to take the hit on max.SPL.

Chris
 
IMO, it might be worth going for a 10" instead of a 12". Both will easily reach down to 1-200Hz to meet the 18", but the 10" will give you the option of a higher crossover point to the compression driver.

Thanks Chris, yea been looking at 12" that can easily go to 2khz but lots more options with a 10" for sure, was just thinking of creating that maximum attack, but if I use a higher crossover of 2-300 for the 18" then certainly the amount of actual bass in the midrange goes away.

Since you've got DSP available, consider a closed box for the 18" - with some dynamic EQ (or a couple of settings that you can switch between), you could get a 20Hz lower cutoff for day-to-day listening, but when you want to crank it, cut off at 35Hz for some serious SPL.
A ported box has pretty much zero useful output below its tuning frequency, whereas sealed can go as low as you want, so long as you're willing to take the hit on max.SPL.
Chris

Good feedback Chris, yes sealed would be a much smaller enclosure as well, I'll play with some options, a lot of the drivers I'm considering have a Q ideal for ported which is why I was leaning that direction. I'm not looking for mega-bass by any means.
 
Everyone who has responded about diffraction, if not cylindrical them assuming rectangular but w/in that, are there certain safe dimensions or ratios I should consider? I've always been a "narrow baffle" sort of guy from a design/aesthetic point of view, I'm always tempted to make it as narrow as possible but certainly want to take diffraction into consideration.

Thanks!
 
Good feedback Chris, yes sealed would be a much smaller enclosure as well, I'll play with some options, a lot of the drivers I'm considering have a Q ideal for ported which is why I was leaning that direction. I'm not looking for mega-bass by any means.


Sealed boxes pretty much always need EQ, but ported boxes need a high-pass filter to protect from signals below tuning. Pick your poison.
I like the flexibility and compact size of sealed systems, but ported ones will have lower distortion and more output around the port tuning frequency. Today's modern PA sub drivers make it difficult to get enough port inside the cabinet, though - they have lots of excursion, which means you need lots of port area, meaning very long ports (with all their associated difficulties).

Which drivers are you considering?

Chris
 
Sealed boxes pretty much always need EQ, but ported boxes need a high-pass filter to protect from signals below tuning. Pick your poison.
I like the flexibility and compact size of sealed systems, but ported ones will have lower distortion and more output around the port tuning frequency. Today's modern PA sub drivers make it difficult to get enough port inside the cabinet, though - they have lots of excursion, which means you need lots of port area, meaning very long ports (with all their associated difficulties).

Which drivers are you considering?

Chris

Chris considering this driver https://www.parts-express.com/selenium-18sws800-18-800w-subwoofer--264-387

Well rated, good xmax, would do well sealed in only 2.5 ft. I like sealed boxes too but calculated a feasible ported enclosure with plenty of port area with good velocity as well.
 
Chris considering this driver https://www.parts-express.com/selenium-18sws800-18-800w-subwoofer--264-387

Well rated, good xmax, would do well sealed in only 2.5 ft. I like sealed boxes too but calculated a feasible ported enclosure with plenty of port area with good velocity as well.

Ok found this driver and this is the contender for the time being, models very well in 6 cubic feet ported and will have no trouble hitting 20hz https://www.parts-express.com/dayton-audio-pa465s-8-18-pro-subwoofer-4-vc-8-ohm--295-042
 
Hmm... That Dayton driver isn't actually what I'd call insanely efficient. Even though you'll apparently be using a DSP and a huge stack of poweramps, I'd still suggest using drivers that would fit together even with a passive crossover. This is of course just an opinion, but I think simplicity is desirable no matter what tools you're using to arrive at a point. The less you need to do with your DSP the better.

For a midrange driver I'd look for something that has a nice even response through the midband with no nasty resonances or other problems for at least an octave above and below the passband. I haven't got any solid contenders for a midrange driver, but I took a quick look and B&C seems to have some promising options in the 10-12" range.
 
Hmm... That Dayton driver isn't actually what I'd call insanely efficient. Even though you'll apparently be using a DSP and a huge stack of poweramps, I'd still suggest using drivers that would fit together even with a passive crossover. This is of course just an opinion, but I think simplicity is desirable no matter what tools you're using to arrive at a point. The less you need to do with your DSP the better.

For a midrange driver I'd look for something that has a nice even response through the midband with no nasty resonances or other problems for at least an octave above and below the passband. I haven't got any solid contenders for a midrange driver, but I took a quick look and B&C seems to have some promising options in the 10-12" range.

Thanks for the comment!

I hear you on that, 94db is down from what other drivers offer, however I've modeled about 15 pro audio 18" subwoofers and this unit is up 5-10 db at 40hz over anything else I've looked at under $400. Definitely open to a driver with this low of extension and higher sensitivity, otherwise bumping this unit up 3db won't be a problem, the 18" will also be getting almost double the power the other drivers will be getting as well. Definitely open to options!

I'm liking this midrange and this one currently, read some good things about it and it looks very flat from 100-1000 which would be the widest possible range I'd use it for, the horn I'm currently looking at goes down to 500 if need be and up past 20k

Looking at this compression driver BMS 4550 1" High frequency Compression Driver - BMS 4550 - BMS 4550 1" high frequency compression driver. BMS neodymium 4550 high frequency compression drivers are available here.
 
Hmm... That Dayton driver isn't actually what I'd call insanely efficient. Even though you'll apparently be using a DSP and a huge stack of poweramps, I'd still suggest using drivers that would fit together even with a passive crossover. This is of course just an opinion, but I think simplicity is desirable no matter what tools you're using to arrive at a point. The less you need to do with your DSP the better.

This was also on the list, 96db B&C 18TBW100 18" Professional Subwoofer 8 Ohm
 
I'd take a look at the ferrite version of that B&C driver you've mentioned. It might be a little easier to tame compared to the neo version.

Something like a 1.5kHz crossover point between the mid and the horn might be a good starting point. If you want to go much lower, you'll end up losing some top end, since you'd have to use a larger diaphragm driver. Then there are of course some coaxial compression drivers, but these are quite expensive. And to be honest would add unneccessary complexity.
 
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